Common rechargeable batteries, e.g. the lithium ion battery, can be divided into the energy-type battery and the power-type battery according to their charge and discharge characteristics. The storage energy of the energy-type battery is high, but the power thereof during charge and discharge is low. On the contrary, the storage energy of the power-type battery is low, but the power thereof during charge and discharge is high. Therefore, the two batteries can be used for different purposes according to their characteristics. For example, the energy-type batteries are more suitable for the products requiring longer runtime or energy density, e.g. the cellphone, notebook computer, etc., whereas the power-type battery can be used for the products requiring higher output power or power density, e.g. the electric car, etc.
However, under the low temperature environment (i.e. lower than the normal working temperature of the battery), both the energy-type battery and the power-type battery have a low battery activity. Therefore, when the battery is used under the low temperature environment, the issues of short power supplying time, poor charge/discharge efficiency and easy damage to the battery will occur.
In order to overcome the drawbacks in the prior art, an energy storage device is provided. The particular design in the present invention not only solves the problems described above, but also is easy to be implemented. Thus, the present invention has the utility for the industry.